A conventional thin film capacitor used for an integrated circuit is of a stacked structure in which electrodes are formed of polysilicon. Such thin film capacitors are fabricated to provide capacitor cells subsequently to the formation of transistors and bit lines in a dynamic random access memory, as described on pages 592 to 595 of "International Electron Devices Meeting Digest of Technical Papers, 1988". In the conventional thin film capacitor, there is limitation in the reduction of an area for a capacitor region which is recently required for higher integration of an integrated circuit. Therefore, the area of the capacitor region must be effectively reduced in accordance with the adoption of three-dimensional structureand thin and high dielectric constant films to be used for thin film capacitors. Consequently, silicon oxide films and silicon nitride films having dielectric constants of approximately 7 at most are used for dielectric films of thin film capacitors. Therefore, silicon oxide films must be very thin to be less than 10 nm in thickness to realize a capacitance value as required. On the other hand, leakage current is increased as the thickness of a dielectric film is reduced. For this reason, it is difficult to realize a thickness of dielectric films having a current-voltage characteristics, by which the leakage current is suppressed to be less than a tolerable value. In other words, the leakage current is increased, because the thickness of dielectric films is reduced at the edge of a lower electrode, and electric field is converged thereat, even if an area of an electrode is effectively increased by using cubit structure.
In this situation, it has been proposed that a thickness of dielectric films is made highly thick by using a dielectric material having a dielectric constant represented, for instance, by SrTiO.sub.3 of a dielectric constant as large as 300 at the room temperature, and (Ba, Sr)TiO.sub.3, Pb(Zr, Ti)O.sub.3, Pb(Mg, Nb)O.sub.3, and Pb(Mg, W)O.sub.3 having much larger dielectric constants, so that the leakage current is avoided to flow therethrough. In case where the above described dielectric material having a high dielectric constant is deposited as a film directly on silicon for a lower electrode, the silicon is diffused to the interface between the dielectric film and silicon dioxide (SiO.sub.2) which is a low dielectric constant layer in oxidation atmosphere. In order to avoid this disadvantage, it is considered that the lower electrode is made of Pt/Ta, Pt/Ti or RuOx.
In the conventional thin film capacitor, however, there are disadvantages that a thickness of the high dielectric constant film is reduced at the edge of the lower electrode which is made by a predetermined configuration and the leakage current is inevitably increased due to the convergence of electric field, even if the lower electrode is made of Pt/Ta, Pt/Ti or RuOx. This is because processed residual occurs on side walls of a resist as a mask used for dryetching to carry out fine patterning, when the dielectric film of the high dielectric constant and the lower electrode of Pt/Ta, etc. are patterned by using the resist, so that minute convex and concave configuration is resulted on the periphery of a processed pattern even after the removal of the resist. Consequently, mass-productivity and reproducibility are lowered.